Cleaning those damn switches in cassette decks??

[The Dark force of dance]

Y-ellow Y'all.
	Thanks everyone for the many suggestions. As it happens I've been able to
perform a kind of amalgam of them all. I got one of my mother's syringes
(She's diabetic not a druggy. But sometimes it's hard to tell. Especially
when your mother tries to steel your video recorder. but that's another
story.) Anyway I got one of her syringes and filled it with Metholated
spirits. Metho as you recall is more or less just alcohol with a poison in
it to make you throw up if you drink it. (Perhaps that's what's wrong with
my mother?) Anyway I got some in one of these tiny little syringes and
managed to pump heaps of the stuff into the switch. Two whole syringe
loads. God knows where it all went because hardly any of it came out again.

I jiggled the switch back and forth a lot in between loads of metho and it
all cleaned up very nicely. Enough to then discover that the cassette deck
actually had a few more problems. :(

What I also discovered was that on the board of another cassette deck was
an identical switch. This other cassette deck is a non-starter so I've
removed the switch and am in the process of cleaning it up as suggested.
Pulling it apart,  dipping and cleaning all the contacts and reassembling
it. When I've done that I'll simply swap the switches over and clean the
other one up as a spare.

The problem now with the deck is that the head alignment is screwed and the
tape wanders across the heads fairly aimlessly. The first problem is easy
to fix if the second problem can be overcome. I'm getting a test tape made
up on a production transcription deck which has recently been aligned. This
will be about as accurate as you can get. But the wandering problem I only
have a theory on.

I'm guessing here that it is related to another curious problem the
cassette deck seems to have. I wouldn't have thought this too critical but
when I think about it, it probably has great bearing on the case. The
supply real has very little, if any tension on it. Which means when you
fast forward and stop, the supply real keeps turning until it looses
momentum. This forces a small amount of tape to bunch up inside the
cassette. This slack has to be taken up before it begins to pull the supply
real around again.

Now if my guess is correct, this deck relies on their being some tension in
order for it to pull the tape tight and guide it through the heads. With no
tension on it, the tape could have a propensity to wander. Especially with
large tapes such as C90s. The evidence seems to suggest this with shorter
tapes. C10s and even C30s having little trouble.

The next thing would be to see what I can do about applying tension on the
supply real. And I've never really looked into what's supposed to happen
there. On most of the tape decks I've worked on -big AMPEX 1" machines and
Tascam 3440s etc - they have a break pad which is released by a solenoid.
It applies tension when it's in play mode but is released when the machine
is spooling. I'm guessing they don't so something so complex in cassette
decks. But I guess I'll find out.

Here's fingers crossed I don't have tiny, exploding, spring-loaded bits
flying around the room.

Anyway thanks for all your suggestions. Most appreciated.

be absolutely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The Elementary Urban sanity CD
| |_) | (_| | |_  / /   out now on Transmission Communications
|_,__/ \__,_|\__|/ /    
                / ,__   http://www.all-electric.com
Goodfortune    |_____|